The invention relates to a targeting apparatus for a locking nail.
Locking nails which may be introduced in the lower or upper femur mostly comprise transverse bores through which bone screws are guided in order to securely hold the locking nail in the bone channel. In particular by way of this a rotational securement is obtained.
A particular problem with locking nails is the location of the transverse bores with an implanted nail. For this therefore targeting apparatus are used. One category of targeting apparatus functions with X-rays. The transverse bores of the locking nail in the bone are imaged on a monitor. Further an imaging of the targeting element takes place. In this manner it is possible on the outer side to mark the location which lies on the axis of the transverse bores.
With another category, targeting apparatus are rigidly connected to one end of a nail. A bow-like section comprises at least one through-bore, whose axis is aligned to the axis of the transverse bore of the nail when it is mounted on the targeting apparatus. For guiding the drilling tool or the bone screw it is also known to insert a guiding sleeve through the transverse bore of the targeting apparatus, which is pushed forwards against the outer side of the bone.
Although the guiding sleeve sits fittingly in the transverse bore of the targeting apparatus, however by hand it must be able to be moved relatively easily in order not to make the work of the surgeon more difficult. By way of this however there exists the danger that with the handling of the targeting apparatus or on drilling and also on screwing in bone screws the guiding sleeve slides backwards.